The Pulmonary Immune Effects of Mechanical Ventilation in Patients Undergoing Thoracic Surgery

Protective effect of sevoflurane on lung function of elderly chronic obstructive pulmonary disease patients undergoing total hip arthroplasty

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a common respiratory disorder that affects the elderly population and increases the risk of postoperative pulmonary complications (PPCs) after major surgeries. Sevoflurane is a volatile anesthetic that has been shown to have anti-inflammatory and antioxidant properties and attenuate lung injury in animal models.

AIM

To evaluate the protective effect of sevoflurane on the lung function of elderly COPD patients undergoing total hip arthroplasty (THA).

METHODS

In this randomized controlled trial, we randomly assigned 120 elderly patients with COPD, who were scheduled for THA, to receive either sevoflurane (sevoflurane group) or propofol (propofol group) as the maintenance anesthetic. The primary outcome was the incidence of PPCs within seven days after surgery. The secondary outcomes were changes in the lung function parameters, inflammatory markers, oxidative stress markers, and postoperative pain scores.

RESULTS

The results showed that the incidence of PPCs was significantly lower in the sevoflurane group than in the propofol group (10% vs 25%, P = 0.02). Furthermore, the decline in the forced expiratory volume in 1 s, forced vital capacity, and peak expiratory flow was significantly lesser in the sevoflurane group than in the propofol group at 24 h and 48 h after surgery (P < 0.05). The interleukin-6, tumor necrosis factor-alpha, malondialdehyde, and 8-hydroxy-2 α-deoxyguanosine levels were significantly lower in the sevoflurane group than in the propofol group at 24 h after surgery (P < 0.05). The sevoflurane group showed significantly lower postoperative pain scores than the propofol group at 6 h, 12 h, and 24 h after surgery (P < 0.05).

CONCLUSION

Sevoflurane protects the lung function of elderly COPD patients undergoing THA under general anesthesia by reducing the incidence of PPCs, attenuating inflammatory and oxidative stress responses, and alleviating postoperative pain.

Impact of Lower Tidal Volumes During One-Lung Ventilation: A 2022 Update of the Meta-analysis of Randomized Controlled Trials

OBJECTIVES

To clarify the influence of lower tidal volume (4-7 mL/kg) compared with higher tidal volume (8-15 mL/kg) during one-lung ventilation (OLV) on gas exchange and postoperative clinical outcome.

DESIGN

Meta-analysis of randomized trials.

SETTING

Thoracic surgery.

PARTICIPANTS

Patients receiving OLV.

INTERVENTIONS

Lower tidal volume during OLV.

MEASUREMENTS AND MAIN RESULTS

Primary outcome was PaO2-to-the oxygen fraction (PaO2/FIO2) ratio at the end of the surgery, after the reinstitution of two-lung ventilation. Secondary endpoints included perioperative changes in PaO2/FIO2 ratio and carbon dioxide (PaCO2) tension, airway pressure, the incidence of postoperative pulmonary complications, arrhythmia, and length of hospital stay. Seventeen randomized controlled trials (1,463 patients) were selected. Overall analysis showed that the use of low tidal volume during OLV was associated with a significantly higher PaO2/FIO2 ratio 15 minutes after the start of OLV and at the end of surgery (mean difference 33.7 mmHg [p = 0.02] and mean difference 18.59 mmHg [p < 0.001], respectively). The low tidal volume also was associated with higher PaCO2 values 15 minutes and 60 minutes after the start of OLV and with lower airway pressure, which was maintained during two-lung ventilation after surgery. Moreover, the application of lower tidal volume was associated with fewer postoperative pulmonary complications (odds ratio 0.50; p < 0.001) and arrhythmias (odds ratio 0.58; p = 0.009), with no difference in length of hospital stay.

CONCLUSIONS

The use of lower tidal volume, a component of protective OLV, increases the PaO2/FIO2 ratio, reduces the incidence of postoperative pulmonary complications, and should be considered strongly in daily practice.

Awake uniportal VATS sublobar lung resections in high-comorbidity patients: Single-center early post-operative outcomes

Introduction

Awake minimally invasive Uniportal Video Assisted Thoracic Surgery (U-VATS) represents the last challenge in thoracic surgery that could change the future scenario for high comorbidity patients with early-stage non-small cell lung cancer (NSCLC). We report a single center preliminary experience of awake thoracoscopic uni-portal anatomic and non-anatomic sub-lobar resections in this setting.

Methods

We retrospectively analyzed data collected on a prospective database of patients undergoing U-VATS awake sub-lobar lung resections for NSCLC between September 2021 and September 2022. Inclusion criteria were clinical stage I disease; contraindication to standard lobectomy due to high respiratory function impairment; general anesthesia considered at high risk based on the American Society of Anesthesiologist score and on the Charlson Comorbidity Index. All patients underwent a standardized awake non-intubated anesthesia protocol approved by our institutional board.

Results

They were n = 10 patients: n = 8 wedge resections; n = 2 segmentectomies. We had n = 1 (10%) conversion to standard general anesthesia and n = 1 laryngeal mask support but maintaining spontaneous breathing. N = 5 patients (50%) needed an Intensive Care Unit recovery (mean time = 17.20 h). Mean chest tube duration and Hospital stay were 2.0 and 3.5 days respectively. We did not register 30- days postoperative mortality.

Conclusion

Awake thoracic surgery is a feasible technique, and it could be performed also in high comorbidities' patients without a high rate of complications and allows to operate patients that so far were considered borderline for surgery.

Identifying biomarkers of ventilator induced lung injury during one-lung ventilation surgery: a scoping review

BACKGROUND

Ventilator-induced lung injury (VILI) can occur as a result of mechanical ventilation to two lungs. Thoracic surgery often requires one-lung ventilation (OLV). The potential for VILI is likely higher in OLV. The impact of OLV on development of post-operative pulmonary complications is not well understood. We aimed to perform a scoping review to determine reliable biomarkers of VILI after OLV.

METHODS

A scoping review was performed using Cochrane Collaboration methodology. We searched Medline, EMBASE and SCOPUS. Gray literature was searched. Studies of adult human or animal models without pre-existing lung damage exposed to OLV, with biomarker responses analyzed were included.

RESULTS

After screening 5,613 eligible papers, 89 papers were chosen for full text review, with 29 meeting inclusion. Approximately half (52%, n=15) of studies were conducted in humans in an intra-operative setting. Bronchoalveolar lavage (BAL) & serum analyses with enzyme-linked immunosorbent assay (ELISA)-based assays were most commonly used. The majority of analytes were investigated by a single study. Of the analytes that were investigated by two or more studies (n=31), only 16 were concordant in their findings. Across all sample types and studies 84% (n=66) of the 79 inflammatory markers and 75% (n=6) of the 8 anti-inflammatory markers tested were found to increase. Half (48%) of all studies showed an increase in TNF-α or IL-6.

CONCLUSIONS

A scoping review of the state of the evidence demonstrated that candidate biomarkers with the most evidence and greatest reliability are general markers of inflammation, such as IL-6 and TNF-α assessed using ELISA assays. Studies were limited in the number of biomarkers measured concurrently, sample size, and studies using human participants. In conclusion these identified markers can potentially serve as outcome measures for studies on OLV.

Diagnostic value and safety of medical thoracoscopy under local anesthesia for unexplained diffuse interstitial lung disease: A retrospective study

Objective

We aimed to explore the safety and diagnostic value of medical thoracoscopic lung biopsy in patients with unexplained diffuse interstitial lung disease (ILD) in a single center pilot study.

Method

We retrospectively analyzed clinical and pathological diagnostic data from 52 patients with diffuse ILD undergoing medical thoracoscopic lung biopsy.

Results

Forty-four cases of diffuse ILD were confirmed pathologically, giving a diagnostic rate of 84.6%. Among these 44 patients, 11 patients were diagnosed with cancer, including eight patients with lung adenocarcinoma, three patients with metastases; two from a gastrointestinal malignancy, and one from a granulosa cell tumor of the ovary. There were 17 cases of idiopathic interstitial pneumonia, including nine cases of usual interstitial pneumonia (UIP), four cases of non-specific interstitial pneumonia (NSIP), three cases of cryptogenic organizing pneumonia (COP), and one case of acute interstitial pneumonia (AIP). There were 12 cases of rare interstitial pneumonias, which included six cases of pulmonary alveolar proteinosis, one case each of pulmonary Langerhans cell histiocytosis (LCH) and pulmonary lymphangiomyomatosis, two cases of nodular sarcoidosis, and two cases of chronic eosinophilic pneumonia. We recorded various complications, including bleeding, infection, and pneumothorax. A total of 28 patients (53.8%) experienced at least one of the above complications, but there were no deaths associated with biopsy.

Conclusions

Medical thoracoscopic lung biopsy appears a safe and effective method for diagnosing diffuse ILD of unknown cause but further prospective studies, with larger numbers, including comparison with other established techniques are required.

Ventilation during Lung Resection and Critical Care: Comparative Clinical Outcomes

Recent evidence suggests that outcomes do not meaningfully differ between thoracic surgery patients who are ventilated with a low or higher tidal volume and the effects of low versus higher positive end-expiratory pressure are unclear.

Low tidal volume ventilation alleviates ventilator-induced lung injury by regulating the NLRP3 inflammasome

PURPOSE

Low tidal volume ventilation (LTVV) is a well-known ventilation mode which can improve ventilator-induced lung injury (VILI). However, the mechanism of LTVV ameliorating VILI has not yet been elucidated. In this study, we aimed to reveal LTVV protected against VILI by inhibiting the activation of the NLRP3 inflammasome in bronchoalveolar lavage fluid (BALF) from humans and lungs from mice.

MATERIALS AND METHODS

Twenty-eight patients scheduled for video-assisted thoracoscopic esophagectomy were randomized to receive high-tidal-volume ventilation [V_t = 10 mL/kg without positive end-expiratory pressure (PEEP)] or LTVV (V_t = 5 mL/kg along with 5 cm of H₂O PEEP) during one-lung ventilation. BALF was collected before and at the end of surgery. Male C57BL/6 mice received high-tidal-volume ventilation, LTVV or MCC950 (an inhibitor of NLRP3). The activation of the formation of NLRP3 inflammasome in BALF from patients and in lungs from mice were analyzed.

RESULTS

LTTV decreased the peak airway pressure (P_peak), plateau airway pressure (P_plat) and driving pressure (ΔP) during one-lung ventilation. Additionally, LTVV not only inhibited pulmonary infiltration and inflammation caused by mechanical ventilation, but also suppressed the NLRP3 inflammasome activation in BALF from humans. In mice, ventilator-induced inflammatory response and pulmonary edema were suppressed by LTVV with an efficacy comparable to that of MCC950 treatment. Furthermore, LTVV, similar to MCC950, clearly decreased ventilator-induced NLRP3 inflammasome activation.

CONCLUSION

Our study showed that LTVV played a protective role in ventilator-induced lung injury by suppressing the activation of the NLRP3 inflammasome.

TRIAL REGISTRATION

This study was registered in The Chinese Clinical Trial Registry, ChiCTR1900026190 on 25 September 2019.

Perioperative Inflammatory Response and Cancer Recurrence in Lung Cancer Surgery: A Narrative Review

While surgical resection is the gold standard treatment for solid tumors, cancer recurrence after surgery is common. Immunosurveillance of remnant tumor cells is an important protective mechanism. Therefore, maintenance of anti-tumor cell activity and proper levels of inflammatory mediators is crucial. An increasing body of evidence suggests that surgery itself and perioperative interventions could affect these pathophysiological responses. Various factors, such as the extent of tissue injury, perioperative medications such as anesthetics and analgesics, and perioperative management including transfusions and methods of mechanical ventilation, modulate the inflammatory response in lung cancer surgery. This narrative review summarizes the pathophysiological mechanisms involved in cancer recurrence after surgery and perioperative management related to cancer recurrence after lung cancer surgery.

Non-Intubated Thoracic Surgery: Standpoints and Perspectives

Non-intubated video-assisted thoracic surgery (NI-VATS) combines the advantages of a non-intubated surgery with the benefits of a minimally invasive approach. First, NI-VATS is performed in the case of fragile patients when general anesthesia and/or orotracheal intubation can be foreseen as inconvenient. However, NI-VATS indications have been increasingly extended to different patient conditions, considering the increasingly assessed safety and feasibility of the procedure. Currently, the NI-VATS approach is used worldwide for different thoracic surgery procedures, including the management of malignant pleural effusion, surgical treatment of empyema, anatomical and non-anatomical lung resection, and other indications. In fact, this approach has shown to be less impactful than VATS under general anesthesia, allowing for shortened hospitalization and faster recovery after surgery. Besides, NI-VATS is associated with fewer pulmonary complications, less respiratory distress, and a mild systemic inflammatory reaction. For these reasons, this approach should be considered not only in patients with poor cardiac or respiratory function (general functional reserve), but also in other eligible conditions.

We explored the anesthetic and surgical aspects of such an approach, including the management of analgesia, cough reflex, depth of sedation, and intraoperative technical issues to put this approach in perspective.

Thoracic surgery in the non-intubated spontaneously breathing patient

BACKGROUND

The interest in non-intubated video-assisted thoracic surgery (NIVATS) has risen over the last decade and numerous terms have been used to describe this technique. They all have in common, that the surgical procedure is performed in a spontaneously breathing patient under locoregional anaesthesia in combination with intravenous sedation but have also been performed on awake patients without sedation. Evidence has been generated favouring NIVATS compared to one-lung-ventilation under general anaesthesia.

MAIN BODY

We want to give an overview of how NIVATS is performed, and which different techniques are possible. We discuss advantages such as shorter length of hospital stay or (relative) contraindications like airway difficulties. Technical aspects, for instance intraoperative handling of the vagus nerve, are considered from a thoracic surgeon's point of view. Furthermore, special attention is paid to the cohort of patients with interstitial lung diseases, who seem to benefit from NIVATS due to the avoidance of positive pressure ventilation. Whenever a new technique is introduced, it must prove noninferiority to the state of the art. Under this aspect current literature on NIVATS for lung cancer surgery has been reviewed.

CONCLUSION

NIVATS technique may safely be applied to minor, moderate, and major thoracic procedures and is appropriate for a selected group of patients, especially in interstitial lung disease. However, prospective studies are urgently needed.

Converting to Intubation During Non-intubated Thoracic Surgery: Incidence, Indication, Technique, and Prevention

Traditionally, intubated general anesthesia with one-lung ventilation is standard in thoracoscopic surgery. However, in recent decades, non-intubated thoracoscopic surgery (NITS) has become an alternative method to minimize the adverse effects of intubated general anesthesia. Non-intubated procedures result in fewer adverse events than tracheal intubation and general anesthesia, such as intubation-related airway injury, ventilation-induced lung injury, prolonged hospital stay, and postoperative nausea and vomiting. Despite these benefits, surgeons must consider the possibility of converting to intubation during NITS as the conversion rate is between 2 and 11%, varying between regions and learning time. The conversion rate is also affected by race, body size, the learning curve, and the surgical team's preferred methods. There are surgical (e.g., significant respiratory movements, uncontrolled bleeding, hindered surgical fields, large tumor sizes, adhesions) and anesthetic (e.g., hypoxemia, hypercapnia, airway spasms) reasons for converting to intubation. When a conversion is deemed necessary by the surgical team, the members should be well-prepared and act rapidly. Anesthesiologists should also feel comfortable intubating patients in the lateral decubitus position with or without bronchoscopic guidance. Patient selection is the key factor for avoiding conversion into an intubated surgery. Patients with an American Society of Anesthesiologists grade 2 or less, a body mass index <25, and less surgical complexity may be good candidates for NITS. Careful monitoring, adequate anesthesia depth, an experienced surgical team, and sufficient preparation can also prevent conversion. Conversion from a non-intubated into intubated thoracic surgery is unwanted but not inevitable. Therefore, NITS can be successful when performed on select patients by a well-prepared and experienced surgical team and is worthy of recommendation owing to its non-invasiveness.

The Effects of Sevoflurane vs. Propofol for Inflammatory Responses in Patients Undergoing Lung Resection: A Meta-Analysis of Randomized Controlled Trials

Objective: Inflammatory cytokines are increased during one-lung ventilation in patients undergoing lung resection, and this increase can be fatal. Propofol and sevoflurane are the main anesthetics used for these patients. Unfortunately, there is no consensus on the best choice of an anesthetic agent concerning an inflammatory response in patients undergoing lung resection. This meta-analysis aimed to compare the effects of propofol and sevoflurane on the inflammatory response in patients undergoing lung resection.

Methods: We searched electronic databases to identify randomized controlled trials comparing the effects of different anesthetics (sevoflurane vs. propofol) on the inflammatory response. The primary outcome concerned the concentration of systemic inflammatory cytokines. The secondary outcomes concerned the concentrations of inflammatory cytokines in the bronchoalveolar lavage (BAL) fluid from the dependent and independent lung. Random effects analysis of the meta-analyses were performed to synthesize the evidence and to assess the concentrations of inflammatory factors in the sevoflurane and propofol groups.

Results: Eight trials involving 488 participants undergoing lung resection with one-lung ventilation were included. There was no significant difference in the concentrations of systemic interleukin (IL)-6, IL-10, or tumor necrosis factor α between the sevoflurane and propofol groups. Compared with the propofol group, BAL levels of IL-6 in the dependent ventilated lung were decreased in the sevoflurane group (three trials, 256 participants; standardized mean difference [SMD], −0.51; 95% confidence interval [CI], −0.90 to −0.11; p = 0.01; I² = 46%). The BAL levels of IL-6 in the independent ventilated lung were also decreased by sevoflurane (four trials, 362 participants; SMD, −0.70; 95% [CI], −0.93 to −0.47; p < 0.00001; I² = 0%).

Conclusions: There was no difference in the systemic inflammatory response between the sevoflurane and propofol groups. However, compared with propofol, sevoflurane can reduce the local alveolar inflammatory response. Additional research is necessary to confirm whether the inflammatory response is direct or indirect.

[Intraoperative Ventilation Approaches to One-lung Ventilation]

The management of thoracic surgery patients is challenging to the anesthetist, since one-lung ventilation (OLV) includes at least two major conditions: sufficient oxygenation and lung protection. The first is mainly because the ventilation of one lung is stopped while perfusion to that lung continues; the latter is related to the fact that the whole ventilation is applied to only a single lung. Recommendations for maintaining the oxygenation and methods of lung protection may contradict each other (e. g. high vs. low inspiratory oxygen fraction (FiO₂), high vs. low tidal volume, etc.). Therefore, a high degree of pathophysiological understanding and manual skills are required in the management of these patients.In light of recent clinical studies, this review focuses on a current protective strategy for OLV, which includes a possible decrease in FiO₂, lowered V_T, the application of positive end-expiratory pressure (PEEP) to the dependent and continuous positive airway pressure (CPAP) to the non-dependent lung and alveolar recruitment manoeuvres as well. Other approaches such as the choice of anaesthetics, remote ischemic preconditioning, fluid management and pain therapy can support the success of ventilatory strategy. The present work describes new developments that may change the classical approach in this respect.

Tidal volume during 1-lung ventilation: A systematic review and meta-analysis

BACKGROUND

The selection of tidal volumes for 1-lung ventilation remains unclear, because there exists a trade-off between oxygenation and risk of lung injury. We conducted a systematic review and meta-analysis to determine how oxygenation, compliance, and clinical outcomes are affected by tidal volume during 1-lung ventilation.

METHODS

A systematic search of MEDLINE and EMBASE was performed. A systematic review and random-effects meta-analysis was conducted. Pooled mean difference estimated arterial oxygen tension, compliance, and length of stay; pooled odds ratio was calculated for composite postoperative pulmonary complications. Risk of bias was determined using the Cochrane risk of bias and Newcastle-Ottawa tools.

RESULTS

Eighteen studies were identified, comprising 3693 total patients. Low tidal volumes (5.6 [±0.9] mL/kg) were not associated with significant differences in partial pressure of oxygen (-15.64 [-88.53-57.26] mm Hg; P = .67), arterial oxygen tension to fractional intake of oxygen ratio (14.71 [-7.83-37.24]; P = .20), or compliance (2.03 [-5.22-9.27] mL/cmH2O; P = .58) versus conventional tidal volume ventilation (8.1 [±3.1] mL/kg). Low versus conventional tidal volume ventilation had no significant impact on hospital length of stay (-0.42 [-1.60-0.77] days; P = .49). Low tidal volumes are associated with significantly decreased odds of pulmonary complications (pooled odds ratio, 0.40 [0.29-0.57]; P < .0001).

CONCLUSIONS

Low tidal volumes during 1-lung ventilation do not worsen oxygenation or compliance. A low tidal volume ventilation strategy during 1-lung ventilation was associated with a significant reduction in postoperative pulmonary complications.

Dexmedetomidine Improves Lung Function by Promoting Inflammation Resolution in Patients Undergoing Totally Thoracoscopic Cardiac Surgery

Objective

Totally thoracoscopic cardiac surgery under cardiopulmonary bypass combined with one-lung ventilation has been identified as the trend in cardiac surgery. The aim of this study was to examine the effects of the selective α ₂ adrenergic receptor agonist dexmedetomidine on the pulmonary function of patients who underwent mitral valve surgery using the totally thoracoscopic technique.

Methods

Fifty-seven patients who underwent thoracoscopic mitral valve surgery between July 2019 and December 2019 were selected. The patients were randomly divided into the control (Con) group (n = 28) and the dexmedetomidine (DEX) group (n = 29) using the random number table method. Arterial blood gas analyses were performed, and the oxygenation (PaO₂/FiO₂) and respiratory indexes (P(A-a)O/PaO₂) were calculated 5 min after tracheal intubation (T1), 2 h after operation (T2), 6 h after operation (T3), and 24 h after operation (T4). Moreover, the serum cytokines interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and intercellular adhesion molecule-1 (ICAM-1) were detected using the enzyme-linked immunosorbent method at all time points. Chest radiography was performed 24 h after surgery. Peripheral blood samples were collected before and after the operation for a complete hemogram. Additionally, the procalcitonin concentration was measured and recorded when the patients were transported to the intensive care unit (ICU). The postoperative extubation time, length of ICU stay, and pulmonary infection rate were also recorded.

Results

Inflammatory reaction after surgery was evident. However, the inflammatory cytokines IL-6, TNF-α, and ICAM-1 in the DEX group were lower than those in the Con group after surgery (T2 to T4; P < 0.05). Neutrophil counts and procalcitonin concentration were higher in the Con group than in the DEX group (P < 0.05). In addition, in the DEX group, pulmonary exudation on chest radiography was lower, and pulmonary function, as shown by an increase in oxidation index and decrease in the respiratory index, improved after surgery (P < 0.05). Moreover, the duration of mechanical ventilation in the Con group was 3.4 h longer than that in the DEX group.

Conclusion

Dexmedetomidine has a protective effect on pulmonary function in patients undergoing mitral valve surgery using a totally video-assisted thoracoscopic technique, which may be related to a reduction in the concentration of inflammatory cytokines in the early perioperative period.

Intraoperative Anesthetic Management of the Thoracic Patient

The intraoperative anesthetic management for thoracic surgery can impact a patient's postoperative course, especially in patients with significant lung disease. One-lung ventilation poses an inherent risk to patients, including hypoxemia, acute lung injury, and right ventricular dysfunction. Patient-specific ventilator management strategies during one-lung ventilation can reduce postoperative morbidity.

In vitro characterization of PrismaLung+: a novel ECCO2R device

BACKGROUND

Invasive mechanical ventilation is lifesaving in the setting of severe acute respiratory failure but can cause ventilation-induced lung injury. Advances in extracorporeal CO₂ removal (ECCO₂R) technologies may facilitate more protective lung ventilation in acute respiratory distress syndrome, and enable earlier weaning and/or avoid invasive mechanical ventilation entirely in chronic obstructive pulmonary disease exacerbations. We evaluated the in vitro CO₂ removal capacity of the novel PrismaLung+ ECCO₂R device compared with two existing gas exchangers.

METHODS

The in vitro CO₂ removal capacity of the PrismaLung+ (surface area 0.8 m², Baxter) was compared with the PrismaLung (surface area 0.35 m², Baxter) and A.L.ONE (surface area 1.35 m², Eurosets) devices, using a closed-loop bovine blood-perfused extracorporeal circuit. The efficacy of each device was measured at varying pCO₂ inlet (p_inCO₂) levels (45, 60, and 80 mmHg) and blood flow rates (Q_B) of 200-450 mL/min; the PrismaLung+ and A.L.ONE devices were also tested at a Q_B of 600 mL/min. The amount of CO₂ removed by each device was assessed by measurement of the CO₂ infused to maintain circuit equilibrium (CO₂ infusion method) and compared with measured CO₂ concentrations in the inlet and outlet of the CO₂ removal device (blood gas analysis method).

RESULTS

The PrismaLung+ device performed similarly to the A.L.ONE device, with both devices demonstrating CO₂ removal rates ~ 50% greater than the PrismaLung device. CO₂ removal rates were 73 ± 4.0, 44 ± 2.5, and 72 ± 1.9 mL/min, for PrismaLung+, PrismaLung, and A.L.ONE, respectively, at Q_B 300 mL/min and p_inCO₂ 45 mmHg. A Bland-Altman plot demonstrated that the CO₂ infusion method was comparable to the blood gas analysis method for calculating CO₂ removal. The resistance to blood flow across the test device, as measured by pressure drop, varied as a function of blood flow rate, and was greatest for PrismaLung and lowest for the A.L.ONE device.

CONCLUSIONS

The newly developed PrismaLung+ performed more effectively than PrismaLung, with performance of CO₂ removal comparable to A.L.ONE at the flow rates tested, despite the smaller membrane surface area of PrismaLung+ versus A.L.ONE. Clinical testing of PrismaLung+ is warranted to further characterize its performance.

Thoracoscopic lung biopsy under regional anesthesia for interstitial lung disease

BACKGROUND

Interstitial lung disease (ILD) management guidelines support lung biopsy-guided therapy. However, the high mortality associated with thoracoscopic lung biopsy using general anesthesia (GA) in patients with ILD has deterred physicians from offering this procedure and adopt a diagnostic approach based on high-resolution CT. Here we report that thoracoscopy under regional anesthesia could be a safer alternative for lung biopsy and effectively guide ILD treatment.

METHODS

This was a single-center retrospective review of prospectively maintained database and consisted of patients who underwent thoracoscopic lung biopsy between March 2016 and March 2018. Patients were divided into two groups: (A) GA, and (B) regional anesthesia using monitored anesthesia care (MAC) and thoracic epidural anesthesia (TEA).

RESULTS

During the study period, 44 patients underwent thoracoscopic lung biopsy. Of these, 15 underwent MAC/TEA. There were no significant differences between the two groups with regard to pulmonary function test and clinicodemographic profile. However, operative time and hospital stay were shorter in MAC/TEA group (32.5±18.5 min vs 50.8±18.4; p=0.004, 1.0±1.3 days vs 10.0±34.7 days; p<0.001, respectively). Eight patients in the GA group, but none in the MAC/TEA group, experienced worsening of ILD after lung biopsy (p=0.03). Additionally, one patient in the GA group died due to acute ILD worsening. No cases of MAC/TEA group had to be converted to GA. In all cases a pathological diagnosis could be made.

CONCLUSIONS

Thoracoscopy using regional anesthesia might be a safer alternative to lung biopsy in patients with ILD.

Physiologic Evaluation of Ventilation Perfusion Mismatch and Respiratory Mechanics at Different Positive End-expiratory Pressure in Patients Undergoing Protective One-lung Ventilation

BACKGROUND

Arterial oxygenation is often impaired during one-lung ventilation, due to both pulmonary shunt and atelectasis. The use of low tidal volume (VT) (5 ml/kg predicted body weight) in the context of a lung-protective approach exacerbates atelectasis. This study sought to determine the combined physiologic effects of positive end-expiratory pressure and low VT during one-lung ventilation.

METHODS

Data from 41 patients studied during general anesthesia for thoracic surgery were collected and analyzed. Shunt fraction, high V/Q and respiratory mechanics were measured at positive end-expiratory pressure 0 cm H2O during bilateral lung ventilation and one-lung ventilation and, subsequently, during one-lung ventilation at 5 or 10 cm H2O of positive end-expiratory pressure. Shunt fraction and high V/Q were measured using variation of inspired oxygen fraction and measurement of respiratory gas concentration and arterial blood gas. The level of positive end-expiratory pressure was applied in random order and maintained for 15 min before measurements.

RESULTS

During one-lung ventilation, increasing positive end-expiratory pressure from 0 cm H2O to 5 cm H2O and 10 cm H2O resulted in a shunt fraction decrease of 5% (0 to 11) and 11% (5 to 16), respectively (P < 0.001). The PaO2/FIO2 ratio increased significantly only at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). Driving pressure decreased from 16 ± 3 cm H2O at a positive end-expiratory pressure of 0 cm H2O to 12 ± 3 cm H2O at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). The high V/Q ratio did not change.

CONCLUSIONS

During low VT one-lung ventilation, high positive end-expiratory pressure levels improve pulmonary function without increasing high V/Q and reduce driving pressure.

Rationale and design of PASSAT - patients' satisfaction with local or general anaesthesia in video-assisted thoracoscopic surgery: study protocol for a randomised controlled trial with a non-randomised side arm

BACKGROUND

Although general anaesthesia (GA) with one-lung ventilation is the current standard of care, minor thoracoscopic surgery, i.e. treatment of pleural effusions, biopsies and small peripheral pulmonary wedge resections, can also be performed using local anaesthesia (LA), analgosedation and spontaneous breathing. Whilst the feasibility and safety of LA have been demonstrated, its impact on patient satisfaction remains unclear. Most studies evaluating patient satisfaction lack control groups or do not meet psychometric criteria. We report the design of the PASSAT trial (PAtientS' SATisfaction in thoracic surgery - general vs. local anaesthesia), a randomised controlled trial with a non-randomised side arm.

METHODS

Patients presenting for minor thoracoscopic surgery and physical eligibility for GA and LA are randomised to surgery under GA (control group) or LA (intervention group). Those who refuse to be randomised are asked to attend the study on the basis of their own choice of anaesthesia (preference arm) and will be analysed separately. The primary endpoint is patient satisfaction according to a psychometrically validated questionnaire; secondary endpoints are complication rates, capnometry, actual costs and cost effectiveness. The study ends after inclusion of 54 patients in each of the two randomised study groups.

DISCUSSION

The PASSAT study is the first randomised controlled trial to systematically assess patients' satisfaction depending on LA or GA. The study follows an interdisciplinary approach, and its results may also be applicable to other surgical disciplines. It is also the first cost study based on randomised samples. Comparison of the randomised and the non-randomised groups may contribute to satisfaction research.

TRIAL REGISTRATION

German Clinical Trials Register, DRKS00013661 . Registered on 23 March 2018.

Management of 1-Lung Ventilation-Variation and Trends in Clinical Practice: A Report From the Multicenter Perioperative Outcomes Group

BACKGROUND

Lung-protective ventilation (LPV) has been demonstrated to improve clinical outcomes in surgical patients. There are very limited data on the current use of LPV for patients undergoing 1-lung ventilation (1LV) despite evidence that 1LV may be a particularly important setting for its use. In this multicenter study, we report trends in ventilation practice for patients undergoing 1LV.

METHODS

The Multicenter Perioperative Outcomes Group database was used to identify patients undergoing 1LV. We retrieved and calculated median initial and overall tidal volume (VT) for the cohort and for high-risk subgroups (female sex, obesity [body mass index >30 kg/m], and short stature), percentage of patients receiving positive end-expiratory pressure (PEEP) ≥5 cm H2O, LPV during 1LV (VT ≤ 6 mL/kg predicted body weight [PBW] and PEEP ≥5 cm H2O), and ventilator driving pressure (ΔP; plateau airway pressure - PEEP).

RESULTS

Data from 5609 patients across 4 institutions were included in the analysis. Median VT was calculated for each case and since the data were normally distributed, the mean is reported for the entire cohort and subgroups. Mean of median VT during 1LV for the cohort was 6.49 ± 1.82 mL/kg PBW. VT (mL/kg PBW) for high-risk subgroups was significantly higher; 6.86 ± 1.97 for body mass index ≥30 kg/m, 7.05 ± 1.92 for female patients, and 7.33 ± 2.01 for short stature patients. Mean of the median VT declined significantly over the study period (from 6.88 to 5.72; P < .001), and the proportion of patients receiving LPV increased significantly over the study period (from 9.1% to 54.6%; P < .001). These changes coincided with a significant decrease in ΔP during the study period, from 19.4 cm H2O during period 1 to 17.3 cm H2O in period 12 (P = .003).

CONCLUSIONS

Despite a growing awareness of the importance of protective ventilation, a large proportion of patients undergoing 1LV continue to receive VT PEEP levels outside of recommended thresholds. Moreover, VT remains higher and LPV less common in high-risk subgroups, potentially placing them at elevated risk for iatrogenic lung injury.

Can apneic oxygen insufflation become a novel lung protective ventilation strategy? A randomized, controlled, blinded, single center clinical trial

Objective

The aim of this study was to determine whether a AOI strategy on non-ventilated lung could reduce the regional and systemic proinflammatory cytokine and oxidative stress response associated with esophagectomy, and to evaluate whether AOI can be used as a novel lung protective ventilation strategy. Its impact on oxygenation after OLV, surfactant protein A, B, C (SP-A, B, C), postoperative hospital stay and postoperative pulmonary complications (PPCs) was also evaluated.

Methods

Fifty-four adults (ASA II-III) undergoing esophagectomy with OLV were enrolled in the study. Patients were randomly assigned into 2 groups: control group (group C) and treated group (group T). Group C was treated with traditional OLV mode,while group T was given AOI of 5 L/min oxygen on the non-ventilated lung immediately at the beginning of OLV. Arterial blood gas was analyzed before and after OLV. A bronchoalveolar lavage(BAL) was performed after OLV on the non-ventilated lung. Proinflammatory cytokine, oxidative stress markers(TNF-α, NF-κB,sICAM-1,IL-6,IL-10,SOD,MDA) and SP-A, B, C were analyzed in serum and BALF as the primary endpoint.The clinical outcome determined by PPCs was assessed as the secondary endpoint.

Results

Patients with AOI had better oxygenation in the recovery period, oxygenation index(OI) (394[367–426] and 478[440–497]mmHg, respectively) of group T at T₂ and T₃ were significantly higher than those (332[206–434] and 437[331–512]mmHg, respectively) of group C. OLV resulted in an increase in the measured inflammatory markers in both groups, however, the increase of inflammatory markers upon OLV in the group C was significantly higher than those of group T. OLV resulted in an increase in the measured SP-A, B, C in serum of both groups. However, the levels of SP-A, B, C of group T were lower than those of group C in serum after OLV, and the results in BALF were the opposite. The BALF levels of SOD(23.88[14.70–33.93]U/ml) of group T were higher than those(15.99[10.33–24.16] U/ml) of group C, while the levels of MDA in both serum and BALF of group T(8.60[4.14–9.85] and 1.88[1.33–3.08]nmol/ml, respectively) were all lower than those of group C (11.10[6.57–13.75] and 1.280[1.01–1.83]nmol/ml) after OLV. There was no statistical difference between the two groups in terms of postoperative hospital stay and the incidence of PPCs.

Conclusion

AOI on non-ventilated lung during OLV can improve the oxygenation function after OLV, relieve the inflammatory and oxidative stress response in the systemic and non-ventilated lung after OLV associated with esophagectomy.

Trial registration

ChiCTR-IOR-17011037. Registered on 31 March 2017.

Peep titration based on the open lung approach during one lung ventilation in thoracic surgery: a physiological study

BACKGROUND

During thoracic surgery in lateral decubitus, one lung ventilation (OLV) may impair respiratory mechanics and gas exchange. We tested a strategy based on an open lung approach (OLA) consisting in lung recruitment immediately followed by a decremental positive-end expiratory pressure (PEEP) titration to the best respiratory system compliance (C_RS) and separately quantified the elastic properties of the lung and the chest wall. Our hypothesis was that this approach would improve gas exchange. Further, we were interested in documenting the impact of the OLA on partitioned respiratory system mechanics.

METHODS

In thirteen patients undergoing upper left lobectomy we studied lung and chest wall mechanics, transpulmonary pressure (P_L), respiratory system and transpulmonary driving pressure (ΔP_RS and ΔP_L), gas exchange and hemodynamics at two time-points (a) during OLV at zero end-expiratory pressure (OLV_pre-OLA) and (b) after the application of the open-lung strategy (OLV_post-OLA).

RESULTS

The external PEEP selected through the OLA was 6 ± 0.8 cmH₂O. As compared to OLV_pre-OLA, the PaO₂/FiO₂ ratio went from 205 ± 73 to 313 ± 86 (p = .05) and C_L increased from 56 ± 18 ml/cmH₂O to 71 ± 12 ml/cmH₂O (p = .0013), without changes in C_CW. Both ΔP_RS and ΔP_L decreased from 9.2 ± 0.4 cmH₂O to 6.8 ± 0.6 cmH₂O and from 8.1 ± 0.5 cmH₂O to 5.7 ± 0.5 cmH₂O, (p = .001 and p = .015 vs OLV_pre-OLA), respectively. Hemodynamic parameters remained stable throughout the study period.

CONCLUSIONS

In our patients, the OLA strategy performed during OLV improved oxygenation and increased C_L and had no clinically significant hemodynamic effects. Although our study was not specifically designed to study ΔP_RS and ΔP_L, we observed a parallel reduction of both after the OLA.

TRIAL REGISTRATION

TRN: ClinicalTrials.gov , NCT03435523 , retrospectively registered, Feb 14 2018.

Data on the effects of remote ischemic preconditioning in the lungs after one-lung ventilation

This article contains data on experimental endpoints of a randomized controlled animal trial. Fourteen healthy piglets underwent mechanical ventilation including injurious one-lung ventilation (OLV), seven of them experienced four cycles of remote ischemic preconditioning (RIP) on one hind limb immediately before OLV, seven of them did not receive RIP and served as controls, in a randomized manner. The two major endpoints were (1) pulmonary damage assessed with the diffuse alveolar damage (DAD) score and (2) the inflammatory response assessed by cytokine concentrations in serum and in bronchoalveolar lavage fluids (BAL). The cytokine levels in the homogenized lung tissue samples are presented in the original article. Further interpretation and discussion of these data can be found in Bergmann et al. (in press).

The Potential Dangers of Recruitment Maneuvers During One Lung Ventilation Surgery

BACKGROUND

Existing evidence regarding lung-protective ventilation (LPV) during one-lung ventilation (OLV) focuses on surrogate outcomes. Our objective was to assess whether an LPV protocol during OLV surgery is associated with reduced respiratory complications.

MATERIALS AND METHODS

This was a matched control retrospective cohort study of patients undergoing pulmonary resection at a tertiary Canadian hospital. The experimental group (n = 50) was derived from primary data of two crossover RCTs, which utilized protocolized LPV strategies with varying levels of positive end-expiratory pressure and recruitment maneuvers. The control group was drawn from a prospectively maintained database; these patients received conventional nonprotocolized ventilation (2000-2010). Each experimental group patient was matched 1:1 with a control group patient with respect to clinically relevant variables (age, sex, diagnosis, smoking status, cardiovascular disease status, comorbidity, BMI, preoperative forced expiratory volume in 1 s, surgery type). Major respiratory complications were defined as composite of acute respiratory distress syndrome, need for new positive-pressure ventilation, and atelectasis requiring bronchoscopy. Paired and unpaired statistical tests were used.

RESULTS

Patients appeared well matched. Major respiratory complications occurred in 8% (n = 4) and 2% (n = 1) of patients in experimental and control groups, respectively (P = 0.50). There was a trend toward increased mortality (4 versus 0, P = 0.06) with protocolized LPV. The patients who died had respiratory complications; one had acute respiratory distress syndrome and two had profound hypoxemia.

CONCLUSIONS

There was a nonsignificant trend toward increased mortality with LPV during OLV. Although limited by a small sample size, our findings identify a potential danger to excessive recruitment maneuvers. Larger studies, with clinically important outcomes are needed to better define the risk/benefit trade-offs for LPV during OLV.

Mechanical ventilation management during cardiothoracic surgery: an open challenge

Mechanical ventilation during surgery is a highly complex procedure, particularly in cardiothoracic surgery, where patients need to undergo substantial hemodynamic management, involving large fluid exchanges and pharmacological manipulation of vascular resistance, as well as direct manipulation of the lungs themselves. Cardiothoracic surgery is burdened by a high rate of postoperative pulmonary complication (PPC), comorbidity, and mortality. Recent trials have examined various techniques to preserve lung function, although consensus on best practice has yet to be reached. This might be due to the close relationship between the circulatory and pulmonary systems. The use of a technique designed to prevent pulmonary complication might negatively impact the hemodynamics of an already critical patient. Stress-induced lung injury can occur during surgery for various reasons, some of which have yet to be fully investigated. In cardiac surgery, this damage is mainly ascribed to two events: cardiopulmonary bypass (CPB) and sternotomy. In thoracic surgery, on the other hand, overdistention and permissive hyperoxia, both routinely used on one lung to compensate for the collapse of the other, are generally to blame for lung injury. In recent years "protective" ventilation strategies have been proposed to spare lung parenchyma from stress-induced damage. Despite the growing interest in protective ventilation techniques, there are still no clear international guidelines for mechanical ventilation in cardiothoracic surgery. However, some recent progress has been made, with positive clinical outcomes.

Effects of Intraoperative Infusion of Esmolol on Systemic and Pulmonary Inflammation in a Porcine Experimental Model of Lung Resection Surgery

BACKGROUND

Lung resection surgery (LRS) is associated with systemic and pulmonary inflammation, which can affect postoperative outcomes. Activation of β-adrenergic receptors increases the expression of proinflammatory and anti-inflammatory mediators, and their blockade may attenuate the systemic inflammatory response. The aim of this study was to analyze the effect of a continuous perioperative intravenous perfusion of esmolol on postoperative pulmonary edema in an experimental model of LRS requiring periods of one-lung ventilation (OLV).

METHODS

Twenty-four large white pigs were randomly assigned to 3 groups: control (CON), esmolol (ESM), and sham. The ESM group received an intravenous esmolol bolus (0.5 mg/kg) and then an esmolol infusion (0.05 mg·kg·minute) throughout the procedure. The CON group received the same volume of 0.9% saline solution as the ESM group plus a continual infusion of saline. The sham group underwent a left thoracotomy without LRS or OLV. At the end of the LRS, the animals were awakened, and after 24 hours, they underwent general anesthesia again. Lung biopsies and plasma samples were obtained to analyze the levels and expression of inflammatory mediators, and the animals also received a bronchoalveolar lavage.

RESULTS

At 24 hours after the operation, the ESM group had less lung edema and lower expression of the proinflammatory biomarkers tumor necrosis factor (TNF) and interleukin (IL)-1 compared to the CON group for both lung lobes. For the mediastinal lobe biopsies, the mean difference and 95% confidence interval (CI) between the groups for edema, TNF, and IL-1 were 14.3 (95% CI, 5.6-23.1), P = .002; 0.19 (95% CI, 0.07-0.32), P = .002; and 0.13 (95% CI, 0.04-0.22), P = .006, respectively. In the left upper lobe, the mean differences for edema, TNF, and IL-1 were 12.4 (95% CI, 4.2-20.6), P = .003; 0.25 (95% CI, 0.12-0.37), P < .001; and 0.3 (95% CI, 0.08-0.53), P = .009.

CONCLUSIONS

Our results suggest that esmolol reduces lung edema and inflammatory responses in the intraoperative and postoperative periods in animals that underwent LRS with OLV.

Effect of combining a recruitment maneuver with protective ventilation on inflammatory responses in video-assisted thoracoscopic lobectomy: a randomized controlled trial

BACKGROUND

We hypothesized that the addition of a recruitment maneuver to protective ventilation (PVRM) would result in lower pulmonary and systemic inflammatory responses than traditional ventilation or protective ventilation (PV) alone in patients undergoing lung surgery.

METHODS

Sixty patients who underwent scheduled thoracoscopic lobectomy were randomly assigned to three groups: traditional ventilation, PV, or PVRM. Ventilations were performed using a tidal volume of 10 mL/kg for the traditional ventilation group and either 8 mL/kg (two-lung) or 6 mL/kg (one-lung, OLV) with a positive end-expiratory pressure of 5 cm H₂O for the PV and PVRM groups. The RM was performed 10 min after the start of OLV. Fiberoptic bronchoalveolar lavage (BAL) was performed twice in dependent and non-dependent lungs: before the start and immediately after the end of OLV. Blood samples were collected at the same time points. The levels of cytokines, including TNF-α, IL-1β, IL-6, IL-8, and IL-10, were measured.

RESULTS

After OLV, the level of TNF-α in the BAL fluid of dependent lungs was significantly higher in the PV than in the PVRM group (P = 0.049), whereas IL-1β, IL-6, IL-8, and IL-10 levels were not significantly different among the groups. In non-dependent lung BAL fluid, no cytokines were significantly different among the groups. After OLV, IL-10 serum levels were significantly higher in the traditional ventilation than in the PVRM group (P = 0.027).

CONCLUSIONS

Lower inflammatory responses in the ventilated lung and serum were observed with PVRM than with traditional ventilation or PV alone. Larger multi-center clinical trials are warranted to confirm the effects of different ventilatory strategies on postoperative outcomes.

Nonintubated-Awake Anesthesia for Uniportal Video-Assisted Thoracic Surgery Procedures

Nonintubated video-assisted thoracic surgery (VATS) strategies are gaining popularity. This review focuses on noninutbated VATS, and discusses advantages, indications, anesthetic techniques, and approaches to intraoperative crisis management. Advances in endoscopic, endovascular, and robotic techniques have expanded the range of surgical procedures that can be performed in a minimally invasive fashion. The nonintubated thoracoscopic approach has been adapted for use with major lung resections. The need for general anesthesia and endotracheal intubation has been reexamined, such that regional or epidural analgesia may be sufficient for cases where lung collapse can be accomplished with spontaneous ventilation and an open hemithorax.

Effects of Dexmedetomidine Infusion on Inflammatory Responses and Injury of Lung Tidal Volume Changes during One-Lung Ventilation in Thoracoscopic Surgery: A Randomized Controlled Trial

One-lung ventilation in thoracic surgery provokes profound systemic inflammatory responses and injury related to lung tidal volume changes. We hypothesized that the highly selective a2-adrenergic agonist dexmedetomidine attenuates these injurious responses. Sixty patients were randomly assigned to receive dexmedetomidine or saline during thoracoscopic surgery. There is a trend of less postoperative medical complication including that no patients in the dexmedetomidine group developed postoperative medical complications, whereas four patients in the saline group did (0% versus 13.3%, p = 0.1124). Plasma inflammatory and injurious biomarkers between the baseline and after resumption of two-lung ventilation were particularly notable. The plasma high-mobility group box 1 level decreased significantly from 51.7 (58.1) to 33.9 (45.0) ng.ml⁻¹ (p < 0.05) in the dexmedetomidine group, which was not observed in the saline group. Plasma monocyte chemoattractant protein 1 [151.8 (115.1) to 235.2 (186.9) pg.ml⁻¹, p < 0.05] and neutrophil elastase [350.8 (154.5) to 421.9 (106.1) ng.ml⁻¹, p < 0.05] increased significantly only in the saline group. In addition, plasma interleukin-6 was higher in the saline group than in the dexmedetomidine group at postoperative day 1 [118.8 (68.8) versus 78.5 (58.8) pg.ml⁻¹, p = 0.0271]. We conclude that dexmedetomidine attenuates one-lung ventilation-associated inflammatory and injurious responses by inhibiting alveolar neutrophil recruitment in thoracoscopic surgery.

Short-term one-lung ventilation does not influence local inflammatory cytokine response after lung resection

Background

One-lung ventilation (OLV) is a ventilation procedure used for pulmonary resection which may results in lung injury. The aim of this study was to evaluate the local inflammatory cytokine response from the dependent lung after OLV and its correlation to VT. The secondary aim was to evaluate the clinical outcome of each patient.

Methods

Twenty-eight consecutive patients were enrolled. Ventilation was delivered in volume-controlled mode with a VT based on predicted body weight (PBW). 5 cmH₂O positive end-expiratory pressure (PEEP) and FiO₂ 0.5 were applied. Bronchoalveolar lavage (BAL) was performed in the dependent lung before and after OLV. The levels of pro-inflammatory interleukins (IL-1α, IL-1β, IL-6, IL-8), tumor necrosis factor alpha (TNFα), vascular endothelial growth factor (VEGF), endothelial growth factor (EGF), monocyte chemoattractant protein-1 (MCP-1) and anti-inflammatory cytokines, such as interleukins (IL-2, IL-4, IL-10) and interferon (IFN-γ), were evaluated. Subgroup analysis: to analyze the VT setting during OLV, all patients were ventilated within a range of 5-10 mL/kg. Thirteen patients, classified as a conventional ventilation (CV) subgroup, received 8-10 mL/kg, while 15 patients, classified as a protective ventilation (PV) subgroup, received 5-7 mL/kg.

Results

Cytokine BAL levels after surgery showed no significant increase after OLV, and no significant differences were recorded between the two subgroups. The mean duration of OLV was 64.44±21.68 minutes. No postoperative respiratory complications were recorded. The mean length of stay was for 4.00±1.41 days in the PV subgroup and 4.45±2.07 days in the CV group; no statistically significant differences were recorded between the two subgroups (P=0.511).

Conclusions

Localized inflammatory cytokine response after OLV was not influenced by the use of different VT. Potentially, the application of PEEP in both ventilation strategies and the short duration of OLV could prevent postoperative complications.

Anesthesia and fast-track in video-assisted thoracic surgery (VATS): from evidence to practice

In thoracic surgery, the introduction of video-assisted thoracoscopic techniques has allowed the development of fast-track protocols, with shorter hospital lengths of stay and improved outcomes. The perioperative management needs to be optimized accordingly, with the goal of reducing postoperative complications and speeding recovery times. Premedication performed in the operative room should be wisely administered because often linked to late discharge from the post-anesthesia care unit (PACU). Inhalatory anesthesia, when possible, should be preferred based on protective effects on postoperative lung inflammation. Deep neuromuscular blockade should be pursued and carefully monitored, and an appropriate reversal administered before extubation. Management of one-lung ventilation (OLV) needs to be optimized to prevent not only intraoperative hypoxemia but also postoperative acute lung injury (ALI): protective ventilation strategies are therefore to be implemented. Locoregional techniques should be favored over intravenous analgesia: the thoracic epidural, the paravertebral block (PVB), the intercostal nerve block (ICNB), and the serratus anterior plane block (SAPB) are thoroughly reviewed and the most common dosages are reported. Fluid therapy needs to be administered critically, to avoid both overload and cardiovascular compromisation. All these practices are analyzed singularly with the aid of the most recent evidences aimed at the best patient care. Finally, a few notes on some of the latest trends in research are presented, such as non-intubated video-assisted thoracoscopic surgery (VATS) and intravenous lidocaine.

Associations between intraoperative ventilator settings during one-lung ventilation and postoperative pulmonary complications: a prospective observational study

Background

The interest in perioperative lung protective ventilation has been increasing. However, optimal management during one-lung ventilation (OLV) remains undetermined, which not only includes tidal volume (V_T) and positive end-expiratory pressure (PEEP) but also inspired oxygen fraction (F_IO₂). We aimed to investigate current practice of intraoperative ventilation during OLV, and analyze whether the intraoperative ventilator settings are associated with postoperative pulmonary complications (PPCs) after thoracic surgery.

Methods

We performed a prospective observational two-center study in Japan. Patients scheduled for thoracic surgery with OLV from April to October 2014 were eligible. We recorded ventilator settings (F_IO₂, V_T, driving pressure (ΔP), and PEEP) and calculated the time-weighted average (TWA) of ventilator settings for the first 2 h of OLV. PPCs occurring within 7 days of thoracotomy were investigated. Associations between ventilator settings and the incidence of PPCs were examined by multivariate logistic regression.

Results

We analyzed perioperative information, including preoperative characteristics, ventilator settings, and details of surgery and anesthesia in 197 patients. Pressure control ventilation was utilized in most cases (92%). As an initial setting for OLV, an F_IO₂ of 1.0 was selected for more than 60% of all patients. Throughout OLV, the median TWA F_IO₂ of 0.8 (0.65-0.94), V_T of 6.1 (5.3-7.0) ml/kg, ΔP of 17 (15-20) cm H₂O, and PEEP of 4 (4-5) cm H₂O was applied. Incidence rate of PPCs was 25.9%, and F_IO₂ was independently associated with the occurrence of PPCs in multivariate logistic regression. The adjusted odds ratio per F_IO₂ increase of 0.1 was 1.30 (95% confidence interval: 1.04-1.65, P = 0.0195).

Conclusions

High F_IO₂ was applied to the majority of patients during OLV, whereas low V_T and slight degree of PEEP were commonly used in our survey. Our findings suggested that a higher F_IO₂ during OLV could be associated with increased incidence of PPCs.

Electronic supplementary material

The online version of this article (10.1186/s12871-018-0476-x) contains supplementary material, which is available to authorized users.

Interaction between peri-operative blood transfusion, tidal volume, airway pressure and postoperative ARDS: an individual patient data meta-analysis

Background

Transfusion of blood products and mechanical ventilation with injurious settings are considered risk factors for postoperative lung injury in surgical Patients.

Methods

A systematic review and individual patient data meta-analysis was done to determine the independent effects of peri-operative transfusion of blood products, intra-operative tidal volume and airway pressure in adult patients undergoing mechanical ventilation for general surgery, as well as their interactions on the occurrence of postoperative acute respiratory distress syndrome (ARDS). Observational studies and randomized trials were identified by a systematic search of MEDLINE, CINAHL, Web of Science, and CENTRAL and screened for inclusion into a meta-analysis. Individual patient data were obtained from the corresponding authors. Patients were stratified according to whether they received transfusion in the peri-operative period [red blood cell concentrates (RBC) and/or fresh frozen plasma (FFP)], tidal volume size [≤7 mL/kg predicted body weight (PBW), 7-10 and >10 mL/kg PBW] and airway pressure level used during surgery (≤15, 15-20 and >20 cmH₂O). The primary outcome was development of postoperative ARDS.

Results

Seventeen investigations were included (3,659 patients). Postoperative ARDS occurred in 40 (7.2%) patients who received at least one blood product compared to 40 patients (2.5%) who did not [adjusted hazard ratio (HR), 2.32; 95% confidence interval (CI), 1.25-4.33; P=0.008]. Incidence of postoperative ARDS was highest in patients ventilated with tidal volumes of >10 mL/kg PBW and having airway pressures of >20 cmH₂O receiving both RBC and FFP, and lowest in patients ventilated with tidal volume of ≤7 mL/kg PBW and having airway pressures of ≤15 cmH₂O with no transfusion. There was a significant interaction between transfusion and airway pressure level (P=0.002) on the risk of postoperative ARDS.

Conclusions

Peri-operative transfusion of blood products is associated with an increased risk of postoperative ARDS, which seems more dependent on airway pressure than tidal volume size.

[Protective effect of dexmedetomidine against perioperative inflammation and on pulmonary function in patients undergoing radical resection of lung cancer]

OBJECTIVE

To study the protective effect of dexmedetomidine against perioperative inflammation and on pulmonary function in patients undergoing radical resection of lung cancer.

METHODS

From May, 2014 to May, 2016, 124 patients with lung cancer receiving radical surgeries were randomized into experimental group (n=62) and control group (n=62). The patients in the control group received a single anesthetic agent for anesthesia, and additional dexmedetomidine was given in the experimental group. The levels of serum interleukin-1β (IL-1β), IL-10, and tumor necrosis factor-alpha (TNF-α) were measured before the operation (T₀), at 30 min (T₁) and 60 min (T₂) during one lung ventilation (OLV) and at the end of operation (T₃). Enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of malondialdehyde (MDA), myeloperoxidase (MPO) and xanthine oxidase (XOD), and the arterial oxygen partial pressure (PaO₂), oxygenation index (OI), airway plateau pressure (APP) and airway resistance (AR) were also recorded.

RESULTS

At the time points of T₁ and T₂, IL-1β, IL-10, MDA, MPO, TNF-α, and XOD levels were significantly increased in both of the groups, but the levels of IL-1, IL-10, TNF-α and MDA were significantly lower and MPO and XOD levels significantly higher in the experimental group than in the control group (P<0.05). In both groups, PaO₂ and OI decreased and APP and AR increased significantly at T₁ and T₂, but APP and AR were significantly lower and PaO₂ and OI significantly higher in the experimental group than in the control group (P<0.05).

CONCLUSION

Anesthesia with dexmedetomidine in lung cancer patients undergoing radical surgery can effectively reduce the inflammatory response of the lungs and protect the lung function of the patients.

Protective Lung Ventilation and Morbidity After Pulmonary Resection: A Propensity Score-Matched Analysis

BACKGROUND

Protective lung ventilation (PLV) during one-lung ventilation (OLV) for thoracic surgery is frequently recommended to reduce pulmonary complications. However, limited outcome data exist on whether PLV use during OLV is associated with less clinically relevant pulmonary morbidity after lung resection.

METHODS

Intraoperative data were prospectively collected in 1080 patients undergoing pulmonary resection with OLV, intentional crystalloid restriction, and mechanical ventilation to maintain inspiratory peak airway pressure <30 cm H2O. Other ventilator settings and all aspects of anesthetic management were at the discretion of the anesthesia care team. We defined PLV and non-PLV as <8 or ≥8 mL/kg (predicted body weight) mean tidal volume. The primary outcome was the occurrence of pneumonia and/or acute respiratory distress syndrome (ARDS). Propensity score matching was used to generate PLV and non-PLV groups with comparable characteristics. Associations between outcomes and PLV status were analyzed by exact logistic regression, with matching as cluster in the anatomic and nonanatomic lung resection cohorts.

RESULTS

In the propensity score-matched analysis, the incidence of pneumonia and/or ARDS among patients who had an anatomic lung resection was 9/172 (5.2%) in the non-PLV compared to the PLV group 7/172 (4.1%; odds ratio, 1.29; 95% confidence interval, 0.48-3.45, P= .62). The incidence of pneumonia and/or ARDS in patients who underwent nonanatomic resection was 3/118 (2.5%) in the non-PLV compared to the PLV group, 1/118 (0.9%; odds ratio, 3.00; 95% confidence interval, 0.31-28.84, P= .34).

CONCLUSIONS

In this prospective observational study, we found no differences in the incidence of pneumonia and/or ARDS between patients undergoing lung resection with tidal volumes <8 or ≥8 mL/kg. Our data suggest that when fluid restriction and peak airway pressures are limited, the clinical impact of PLV in this patient population is small. Future randomized trials are needed to better understand the benefits of a small tidal volume strategy during OLV on clinically important outcomes.

Immunological and Inflammatory Impact of Non-Intubated Lung Metastasectomy

Background: We hypothesized that video-assisted thoracic surgery (VATS) lung metastasectomy under non-intubated anesthesia may have a lesser immunological and inflammatory impact than the same procedure under general anesthesia. Methods: Between December 2005 and October 2015, 55 patients with pulmonary oligometastases (at the first episode) successfully underwent VATS metastasectomy under non-intubated anesthesia. Lymphocytes subpopulation and interleukins 6 and 10 were measured at different intervals and matched with a control group composed of 13 patients with similar clinical features who refused non-intubated surgery. Results: The non-intubated group demonstrated a lesser reduction of natural killer lymphocytes at 7 days from the procedure (p = 0.04) compared to control. Furthermore, the group revealed a lesser spillage of interleukin 6 after 1 (p = 0.03), 7 (p = 0.04), and 14 (p = 0.05) days. There was no mortality in any groups. Major morbidity rate was significantly higher in the general anesthesia group 3 (5%) vs. 3 (23%) (p = 0.04). The median hospital stay was 3.0 vs. 3.7 (p = 0.033) days, the estimated costs with the non-intubated procedure was significantly lower, even excluding the hospital stay. Conclusions: VATS lung metastasectomy in non-intubated anesthesia had significantly lesser impact on both immunological and inflammatory response compared to traditional procedure in intubated general anesthesia.